The present invention relates to a transmission for a motor vehicle, of the type comprising a transmission shaft connected to a driving shaft and to a driven shaft by respective constant-speed joints.
The transmission shafts employed in motor vehicles for transmitting power from the drive unit to a driving wheels are provided with constant-speed articulated joints. Some of these joints permit a very free sliding and thus cut off the axial vibrations produced by the drive unit, i.e. prevent such vibrations from reaching the wheels.
But it is known that no constant-speed joint provided for transmission shafts of motor vehicles permits stopping the propagation of radial vibrations of the driving shaft from the drive unit to the wheels and to the structure of the vehicle. This is due to the fact that all these joints are of a mechanical construction which is radially rigid and the filtering of the radial vibrations would require a radial elasticity which is incompatible with the transmission of high torque a small volume, i.e. by a small unit.
French Pat. No. 78 03 978 proposes a device comprising two joints having a very low friction and a support bearing for the transmission shaft, this device constituting an effective dynamic break in the radial vibrations for all radial vibration frequencies produced by the drive unit.
However, in the case of a lateral transmission of a front wheel drive vehicle, the available space is often so small that the use of such a device becomes a problem.